While driving lost all power and engine shut off

I just bought a 88 f150 xlt lariat I drove it to the gas station and got it home when my old lady got home from work we went for a drive we went bout half a mile and it died after cussing and panicking got it back running got to Walgreens and shifted to neutral where it slowly lost power and died I bought a new battery installed it and it still kept dying finally got a block and half from home when it died once more and wouldn't start for several hours when I finally got it home I had a buddy bring his jumpers and it wanted to start but would only crank over its winter season and work is slow so I can't afford buying parts all the time can someone give me a helpful hint as to what it might be